It is known that, in a tire vulcanizing apparatus, an unvulcanized tire (green tire) is enclosed by side molds surrounding the side regions of the unvulcanized tire and a plurality of sector molds surrounding the crown region of the unvulcanized tire, and pressure is applied to the mold interior from outside while a heating medium is supplied to thereby promote the vulcanizing.
Also, known as the methods for producing these molds are primarily die-casting and in recent years rapid prototyping.
Of these methods, die-casting comprises a number of processes including the fabrication of a prototype model and a rubber mold, the fabrication of a mold, and the casting, using a number of intermediate materials. In comparison with this, rapid prototyping has an edge over the die-casting in being able to produce a metal mold based on a 3D model of the metal mold in a short period of time. However, it has a problem of greater likelihood of deformation by thermal strain due to its specificity that each layer is produced by repeating heating and sintering and stacked together. Also, the rapid prototyping is disadvantageous compared to the die-casting in that the cost rises dramatically with the volume of the mold to be produced.
Also, disclosed in Patent Document 1 in particular is a method for producing a sector mold in a short time and at low cost, in which a pattern molding segment made of a thermoplastic resin molded by rapid prototyping is heated, pressurized and assembled on a base segment of an aluminum alloy to produce the sector mold. According to this producing method, however, because the pattern molding segment is made of a resin, the pattern molding segment is easy to wear and deform by the repeated use of the vulcanizing apparatus and thus it is concerned that the durability would be inferior.